Types of Barcode Scanners
Questions to Think About:
- Is your environment hazardous?
- Are you performing multiple transactions at once?
- Are you scanning barcodes or utilizing RFID?
- How much memory does your device need to have?
- Do you need to be mobile?
- Which scan engine will you need, what distance do you need to scan?
- Do you need to read 1D, 2D barcodes or both?
- Are you on a network and want to process real-time?
- Do you have security limitations and requirements?
- Do you need wired or wireless scanner?
There are several types of barcode scanners. The first decision in selecting a barcode scanner is to decide the form factor. Barcode scanners can be:
- The “wand” is the simplest and least expensive input device available. It is durable and contains no moving parts. It must, however, come into contact with the bar code, which can present a challenge. If a bar code must be read more than once, it may become smeared or damaged and, in essence, unreadable. Also, a wand is “human powered,” which means it must be held at the proper angle and moved at the proper speed. For these reasons, a wand is the best choice when cost is the largest determining factor.
- The CCD, or “Charge Couple Device,” is another common input device. A CCD is a very “aggressive” instrument, with a high ability to read bar codes quickly and easily. But it has two primary limitations. First, it has a short “read” range, and must be held no more than 1 to 3 inches from the bar code. Further, the CCD has a limited width, and will not read bar codes that are wider than the face of the input device. It is largely popular for use in point of sale applications.
- The laser scanner is perhaps the most popular bar code input device. A laser scanner need not be close to the bar code to do its job. A standard range laser scanner can read a bar code from about 6 to 24 inches away, and a long range scanner can read one from perhaps 2 to 8 feet away. An extra long-range device can even read a bar code 30 feet from the device. Laser scanners vary in price from $200 to $2,000 and come in a variety of models.
- Imager: It is not possible for a wand, CCD, or laser scanner to read a matrix. Enter the imager. These devices cannot only read matrix codes, but also 1D and other 2D Symbologies. An imager operates like a camera taking a picture of the image. And imagers can be used in the creation of ID cards that require a picture of the person.
- Portable Data Terminals — Sometimes you must bring the computer to the bar code, particularly to handle jobs such as warehouse inventory control or freezer applications. A portable data terminal (PDT), a fully programmable hand-held computer, is necessary in such instances. When a scanner device is integrated into the unit, you have created a powerful data collection device. The most common implementation is an integrated laser scanner, but imagers are now being more available.
Barcode scanners are equipped with a specific scan engine that determines, among other things, the effective scanning distance and most efficient barcode label size.
- Standard: Reads basic 1D bar codes that are between 5 and 20 mils.
- High Density: High-density scanners are used for reading small, dense bar codes, such as those typically found on jewelry tags. This type of scanner might, for example, read down to a 2-mil bar code and up to a 7-mil bar code.
- High Visibility: Remember that a scanner reads what is reflected back to it. However, if the scanner were being used in a very bright environment, the light that would normally be reflected back would be “washed out” by the ambient light, such as sunlight. So a high visibility scanner has a brighter beam of light to overcome this problem.
- Long Range: In a warehouse environment, it is sometimes necessary to read a bar code from a long way away – such as 40 feet. Long Range scanners will typically have an “aiming beam,” which is a bright dot to assist the user in locating the specific bar code that the user wishes to scan. To be able to read a barcode from 40 feet away, the bar code should be very large and printed on material (called “retroreflective”) that can reflect, rather than absorb, a lot of light.
- Omni-directional: All of the above scanners require the bar code to be turned in a specific direction because they only emit a single line. An Omni-directional scanner emits a pattern of several lines. Think about a visit to the grocery store. Can you imagine how slow it would be if the cashier had to make sure that every bar code was turned in a specific direction? Where Omni-directional scanners are being used, the user can have a bottle standing up, or lying on its side, or at an angle as the bottle is presented to the scanner. It doesn’t matter which way the bar code is positioned.
- 2D Scanners: These are not to be confused with Imagers. 2D laser scanners “raster,” which means they scan left to right, right to left, and up and down. Typically, they will only read PDF417 and 1D Symbologies. These scanners also are generally more expensive than conventional 1D scanners.
Bottom Line: TPI will analyze your needs and select the best scanner for your application.